Air handlers for building air conditioning systems have a plurality of cooling coils connected to one or more compressors. The compressors move refrigerants through the cooling coils as air is drawn over the cooling coils to condition the air, usually cooling or heating the air. To promote efficiency some air handlers will have separate cooling coils with each of the cooling coils connected to a corresponding compressor, condenser, and expansion valve. Providing separate cooling coils allows the heating and cooling load of the air handler to be varied by selectively operating less than all of the cooling coils and corresponding compressors. However, during low load conditions air will continue to flow over the cooling coils not being operated while only the air flowing across the active coils is conditioned. Air passing through an air handler is often cooled to control the amount of moisture in conditioned air.